According to the Ecological Valence Theory (EVT), people's color preferences are determined by their average affective response to all “things” associated with those colors (Palmer & Schloss, submitted). Accordingly, preference for a color should increase with increasingly positive feelings for a strong associate of that color (e.g., one's university) and decrease with increasingly negative feelings about that same associate. We tested this prediction by comparing color preference ratings from Berkeley and Stanford undergraduates a few weeks before the intensely rivalrous “Big Game.” The EVT predicts that students should like their own school colors more than their rival's school colors, and that the degree of preference for these colors should be related to their amount of school spirit. Berkeley and Stanford undergraduates, rated their preferences for 40 single colors (37 colors of the Berkeley Color Project plus Berkeley-blue, Berkeley-gold, and Stanford-red) and 42 figure-ground color pairs (all pair-wise permutations of Berkeley-blue, Berkeley-gold, Stanford-red, white, light-blue, dark-yellow and light-red). Participants then rated their degree of agreement with five statements designed to assess school spirit. Total school spirit scores from Berkeley and Stanford were combined into a single bipolar dimension by multiplying the Stanford scores by -1. For single colors, there was a significant positive correlation (r=0.44) between school spirit and the signed difference in preference (Berkeley-blue plus Berkeley-gold minus Stanford-red), showing that Berkeley students like blue and gold more than red, whereas Stanford students like red more than blue and gold. Preference for color pairs showed analogous effects: School spirit was significantly correlated with the difference in preference for pairs containing Berkeley's blue-and-gold and those containing Stanford's red-and-white (r=0.36). These results support the EVT by showing that positive feelings towards one's university promote higher preference for colors associated with that university than for colors associated with a rival university.